DESCRIPTION (As Adapted from the Investigator's Abstract): Thousands of patients receive large volume enemas as a preparation for surgery of diagnostic procedures. The choice of type of solution is based on the effectiveness of different types of solutions. Our preliminary study indicates important difference in effectiveness with hypotonic with irritant solutions yielding better outcomes. No measure of rectal mucosal irritation was examined. The proposed study compares cleansing effectiveness and safety associated with three types of enema solutions: hypotonic, hypotonic with irritant, and isotonic polyethylene glycol electrolyte solution. Using a balanced repeated measures design each type of enema solution will be administered, at one-week intervals, to 24 healthy volunteers. Dependent measures include net enema output, fluid absorption, enema retention time subjects' assessment of discomfort, macroscopic examination of the rectal mucosa to assess cleanliness, and histopathology of rectal mucosa biopsies. Following defecation, subjects will undergo proctoscopy for macroscopic examination and biopsy. Both the individual and the proctologist will be blinded to the type of enema solution. To evaluate the differences associated with type of enema, the data will be examined using a one-way repeated analysis of variance. The results will provide beginning evidence to guide providers' decision about the type of solution use for effective and safe outcomes.